Hazan, Haim (312/12 Zvi Borenstein Street, Yerucham, IL)

09/230537

09/19/2000

01/27/1999

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126/638

126/612, 126/611, 126/639

F24D17/00; F24J2/34; F24J2/04; F24J2/44

126/638, 126/639, 126/612, 126/613, 126/642, 126/641, 126/640, 126/610, 126/611, 165/104.22, 165/104.24

4567878	Solar anti-reverse siphon system	February, 1986	Larkin	126/639
4637375	Integrated solar heating unit	January, 1987	Larkin	126/434
5462047	Solar water-heater with integrated storage	October, 1995	Kleinwachter	126/639

AU488085	May, 1976
FR2590000	May, 1987
IL48555	November, 1975
IL53396	November, 1977
NL8303984	June, 1985
GB1564887	April, 1980

Yeung, James C.

Ostrolenk, Faber, Gerb & Soffen, LLP

1. said housing having an inlet port connected to receive water from saidextended length piping circuit, and an outlet supply port connected toprovide hot water, whereby water passing from said piping into saidhousing is directly heated within said housing by said immersion heater.NUM 2.PAR 2. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, wherein said fluid storagetank is a tub-shaped container having an upper face having an elastomericsheet clamped to said rim and sealing said rim.NUM 3.PAR 3. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, wherein said furtherconduit providing fluid communication between said upper area of saidabsorber panel and said upper area of said storage tank includes a devicearranged to prevent reverse-direction flow.NUM 4.PAR 4. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 3 wherein said devicecomprises a flap-type one-way valve.NUM 5.PAR 5. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, further comprising with adiaphragm connecting said storage tank to the atmosphere.NUM 6.PAR 6. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, wherein the volume of saidimmersion heater housing is at most 15% or less of the volume of saidstorage tank.NUM 7.PAR 7. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, wherein said immersionheater housing has a major axis which is oriented horizontally.NUM 8.PAR 8. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, further comprising with athermostat positioned in said housing located in said upper area of saidstorage tank.NUM 9.PAR 9. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, wherein said immersionheater housing has a major axis oriented horizontally.NUM 10.PAR 10. A low-profile, solar energy powered, thermosyphon-circulated waterheater and storage device according to claim 1, further provided with athermostat positioned in said housing located in an upper area of saidstorage tank.

PAC BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially broken away perspective view of a preferredembodiment of the water heater and storage tank shown as part of a solarwater heating system;

FIG. 2 is a detail sectional view of the electric heater used in the sameembodiment;

FIG. 3 is a fragmented, side elevational view of an embodiment using anelastomeric sheet in the storage tank;

FIG. 4 is a detail view of a device preventing reverse-direction flow inthe thermosyphon circuit and

FIG. 5 is a fragmented side elevational view of an embodiment provided witha diaphragm. PAC DESCRIPTION OF PREFERRED EMBODIMENTS

There is seen in FIG. 1 a low-profile, solar energy powered,thermosyphon-circulated water heater and storage device 10. A flat, tiltedsolar radiation absorber panel 12 is covered with a spaced-apart glasscover sheet 14 in the conventional manner to reduce upward heat losses.The absorber panel 12 is preferably constructed of a pair of aluminiumsheets 12a, 12b, and flow conduits 16 are provided between the sheets 12a,12b for the low-pressure circulation of a fluid 17. Typically suchpressure is 0.3 atm gauge pressure, or less.

Solar radiation is absorbed and converted to heat on the upper surface ofpanel 12a. Preferably, the panel 12a is provided with awavelength-elective coating with high solar radiation absorption and lowlong-wave emittance. Coatings of this type are known to provide acost-effective boost in efficiency, particularly under partially-cloudyconditions.

An insulated hot fluid storage tank 18 is positioned to the rear of theabsorber panel 12. The tank 18 shown in the present embodiment issubstantially oblong. Due to the low pressure to which tank 18 issubjected, there is no need to employ the conventional cylindrical tankused on most prior-art collector systems. The tank 18 can suitably be madeof galvanized sheet steel, glass-reinforced polyester or an unreinforcedthermoplastic protected by the addition of a UV absorbing stabilizer.

A conduit 20 provides fluid communication between a lower area of absorberpanel 12 and storage tank 18. A further conduit 22 provides fluidcommunication between an upper area of absorber panel 12 an upper area ofstorage tank 18 to complete a thermosyphonic path between panel 12 andtank 18, and to facilitate the circulation of fluid heated in absorberpanel 12 into fluid storage tank 18.

Where the device 10 is to be used in a location subject to freezing, thefluid 17 will comprise water with an anti-freeze material added. The useof demineralized water is advantageous to obviate the formation ofdeposits detrimental to good heat transfer.

An extended-length, heat-exchange, piping 24 circuit has an entry port 26for cold, line-pressure water, and an outlet port 28 for hot water. Theextended length is obtained in this embodiment by a pipe bent into aserpentine form having multiple coils. The piping 24 winds through theupper part of the storage tank 18, and from there onto an electric heater30. The piping 24 is arranged to facilitate the transfer of heat betweenfluid 17 held in said storage tank and line-pressure water passing throughpiping 24. Such heat transfer usually takes place from the storage tank tothe heat-exchange piping. Under most circumstances the water received bythe user is not overheated, as is often the case in systems supplyingwater for consumption directly from the absorber system. Conversely, thewater supplied after excessive use becomes cooler gradually using theheat-exchange system, whereas in other systems when water for consumptionis supplied directly from the absorber circuit, water temperature quicklybecomes uncomfortably cold as a result of excessive use.

It is also to be noted that the piping 24 provides hot water to theconsumer at near line pressure, which, in comparison with low pressuresupply systems, saves the time of the user and is of benefit duringshowering. Excessive line pressure is moderated by the bends in the piping24.

An electric water immersion heater 30 is positioned in a housing 32.located in an upper area of storage tank 17, adjacent extended lengthpiping 24. The heater 30, when needed, provides supplementary heat towater passing through piping 24 so as to provide hot water to theconsumer, as well as providing supplementary heat to fluid 17 contained inthe upper area of storage tank 18.

Referring now to FIG. 2 the electric water heater 30 is contained in ahousing 32, having an inlet port 34 connected to receive water from theextended length piping circuit outlet port 28, and an outlet supply port36 connectable to provide hot water to the consumer.

Advantageously, the immersion heater housing 32 has a major axis AAoriented horizontally. The volume of the immersion heater housing 32 is15% or less of the volume of storage tank 18. This is advantageous inmaking possible fast heating to the water being supplied to the consumerat the time of demand.

A thermostat 38, controls the heater element 30, and is preferably locatedin the housing 32. The thermostat 38 causes current cut-off as soon as thesmall volume of water inside the housing 32 reaches set-point temperature.A suitable set-point for general domestic use of the present device is 45degrees C. This arrangement allows the user to leave the heater element 30switched on for extended time periods without causing extensive waste ofelectricity. The housing 32 is arranged to retain water, even during atemporary failure in the incoming supply. The heater element 30 is thusprotected against dry operation and subsequent burn-out.

FIG. 3 illustrates a detail of a further embodiment of low-profile, solarenergy powered, thermosyphon-circulated water heater and storage device52. The fluid storage tank, which is integrated with the absorber panelhousing 56, is a tub-shaped container 54, having an open upper face 58,the rim 60 of which is sealed by an elastomeric sheet 62 clamped to thetub rim 60. The container 54 is readily cleanable by removing orexchanging the elastomeric sheet 62. Changes in fluid volume and pressureare easily accommodated by the elastomeric sheet 62. A suitable materialtherefore is butyl rubber.

The device 52 offers the advantages of an integrated design--it uses lessroof space, is more architecturally acceptable, part of the heat lossesfrom the collector panel rear face enter the storage tank instead of beinglost to the atmosphere, and the preconnected piping saves installationtime.

Seen in FIG. 4 is a detail of a low-profile, solar energy powered,thermosyphon-circulated water heater and storage device 64. The furtherconduit 66 provides fluid communication between (with reference to FIG.1a) an upper area of the absorber panel 12 and an upper area of thestorage tank 18. The device 72 is arranged to substantially preventreverse-direction flow, and the consequent heat losses in the storagecircuit, should the absorber panel 12 become cooler than the contents ofthe storage tank 18. Such a situation is to be expected at nighttime.

The standard type of check-valve, typically based on a spring-loaded ball,is not ideal for this use, as deposits building up on the ball or itsseating are likely to cause serious leakage. In the preferred embodimentshown, the device 72 comprises a flap-type one-way valve. The flap 74 issuspended by a loose-fitting pivot 76 allowing the flap 74 to seal againstthe shoulder 78 should reverse flow occur. Under normal flow conditions,the flap 74 is angled away from the shoulder 78. Such a valve has theadvantage of being able to function acceptably well at a low pressuredifferential even after suffering the effects of mineral deposits whichare to be expected in water heaters.

Referring now to FIG. 5, there is depicted a detail of a low-profile, solarenergy powered, thermosyphon-circulated water heater and storage device80, here further provided with a diaphragm 82 connecting the storage tank84 to the atmosphere. The diaphragm 82 allows for minor volume andpressure changes, and so makes possible the construction of the storagetank 84 out of light-duty materials, including recyclable plastics.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrative embodiments and thatthe present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof. The presentembodiments are therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and all changeswhich come within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.